This invention relates generally to pressure vessel enclosures and in particular to pressure vessel enclosures in which the compression in the enclosure walls can be continuously controlled and adjusted.
This invention also relates to pressure safety enclosures that can be disassembled and assembled for inspection of the primary pressure vessel and its welds with a minimum of time and effort.
Increasingly, in the operation of nuclear reactors, environmental degradation due to corrosion, mechanical or radiation effects on reactor vessel steels and weld materials have become a major concern. In order to extend its useful life, operating pressure or volume, a concept of a prestressed safety enclosure has been developed a nuclear reactor system.
For safety reasons, pressure vessels, particularly nuclear reactor pressure vessels, must be designed so that all pressure or load carrying welds can be inspected periodically. This inspection can be performed on the pressure vessel either prior to service or later while the system is temporarily out of service, such as, during a reactor refueling outage.
Most of the primary pressure vessels of the prior art comprised a single large vessel with one or more openings to gain access to the interior of the vessel. A flanged dome cover, usually fastened by studs to one end of the pressure vessel, provided the primary access to the interior of the vessel. To inspect the interior of the pressure vessel the studs in the peripheral flange surrounding the dome cover had to be removed in order for the dome to be removed.
The main purpose of the pressure safety enclosure (PSE) of the present invention is to contain the fragments of the primary pressure vessel (PPV), the hot radioactive coolant fluid, the fragments of the nuclear core and any fission products in the unlikely event of an explosion, leak or other failure of the primary pressure vessel (PPV).